Bracing bars are often utilized within cargo compartments, such as within a truck, to prevent the shifting of a partial load. Bracing bars may utilize fittings at their ends which are received within fittings mounted upon the partitions and walls of the cargo compartment, or the load bracing bar may be frictionally held in place by frictional engagement of the bar ends with the cargo partitions. The frictionally retained bracing bar is economical, requires no modifications to the cargo compartment, and permits wide latitude in the installment of the bar within the cargo compartment.
Frictionally retained bracing bars commonly utilize means for expanding the length of the bar to accomodate the bar to the particular width of the cargo compartment, and force the ends of the bar into firm frictional engagement with the cargo compartment partitions. Such adjustment is achieved by varying the length of the bar, and retaining the bar at the length which produces the desired functional forces.
Load bracing bars often employ telescopingly interconnected portions to permit adjustment of the bar length, partition engaging friction pads being mounted upon the outer ends of the bar portions. The expanding adjustment of the bar may be produced by springs wherein a biasing force is maintained upon the bar portions to maintain frictional engagement with the partitions. An example of such a spring biased bracing bar is shown in U.S. Pat. No. 3,090,600. Spring biased bracing bars have the advantage of maintaining a uniform frictional engagement with the cargo partitions, but the frictional forces are limited by the biasing forces produced and spring biased bars are usually employed only in light duty applications.
Heavier duty load retaining bars may include a gear and rack arrangement for producing a positive extension of the telescoped bar portions capable of producing high frictional forces between the bar and the cargo partitions. Such bracing bars may utilize a linear toothed rack affixed to one of the bar portions and a pinion gear rotatably mounted upon the other bar portion selectively engages the teeth of the rack for extending the portions into engagement with the cargo partitions. Such bracing bars, as typified in U.S. Pat. No. 3,049,328, are expensive to manufacture in view of the machined tooth rack and gear, and are often bulky and heavy in view of the necessity to attach the rack and gear structure to the bar in a high strength manner.
It is an object of the invention to provide an adjustable load bracing bar capable of producing a positive high pressure bar extension wherein the mechanism for extending the bar is of a simple and economically producible form.
A further object of the invention is to provide an adjustable load bracing bar of a high force producing type wherein a lever and dog mechanism is utilized in conjunction with a toothed track homogeneously defined upon one of the bar portions.
Another object of the invention is to provide an adjustable load bracing bar utilizing a telescoping bar portion having a homogeneous tooth track defined thereon capable of transmitting significant forces and employed in conjunction with a lever mounted dog wherein the homogeneous toothed track construction simplifies manufacture, results in concise design and handling characteristics, and minimizes the number of components as compared with prior art bracing bars.
Yet another object of the invention is to provide an adjustable load bracing bar which may be readily handled and installed by one person, initial longitudinal extension of the bar being manually producible, and such initial expansion being sufficient to retain the bar in place prior to further extension through a lever actuator.
An additional object of the invention is to provide an adjustable load bracing bar utilizing a lever and pivoted dog arrangement wherein the dog cooperates with a homogeneous tooth track, the lever being pivotal between positions which permit the dog to be released from the tooth track for retracting the bar portions, and lever movement permits the spring biased dog to engage the track and longitudinally extend the bar portions during lever operation. Full extension of the bar being retained by a positive acting lever detent.
In the practice of the invention the load bracing bar consists of two telescopingly interconnected portions each having a partition engaging pad at its outer end. One of the bar portions, the inner portion in the disclosed embodiment, includes a tooth track homogeneously formed thereon extending in the longitudinal direction of the bar portion. The tooth track is formed by a stamping or rolling procedure wherein the teeth of the track are formed of the metal of the bar portion and extend transversely to the bar portion length. The toothed bar portion is of a tubular configuration, and includes elongated key means defined thereon for cooperating with a key member mounted upon the other bar portion in order to prevent rotation between the bar portions.
A lever support is mounted upon the inner end of the larger diameter tubular bar portion and includes abutment means for engaging the associated portion inner end to resist axial displacement during bar extension. A pivotal lever mounted upon the lever support includes a linked pivotal dog arrangement which includes a dog biased toward engagement with the toothed track of the other bar portion. The lever is pivotal to a release position wherein the dog is disengaged from the toothed track to permit the bar portions to be retracted, and pivoting of the lever in the opposite direction permits the dog to engage the toothed track, and further pivoting causes the dog to extend the toothed bar portion in an axial direction to increase the length of the bar and produce the frictional engagement with the cargo compartment partitions. Detents mounted upon the lever lock the lever in the bar extended position and require positive manual operation to release the bar from its extended position.